Sedentary activity and obesity threaten the cardiovascular health of nearly one third of U.S. women. Minority women are at particular risk for obesity and tend to engage in less physical activity than their white counterparts. Nurses in community- based treatment programs recognize the importance of physical exercise in weight management, but must rely on laboratory trials and treadmill data to accurately guide recommendations of physical activity. Examinations of the dose-response effect of physical activity have demonstrated that the most significant reductions in rates of CHD are found when sedentary individuals begin to exercise. The dose-response and desirability of low intensity exercise, performed on community sidewalks or field tracks by overweight sedentary women, have not been established. The problem is to develop an exercise protocol that is of low enough intensity that the probability of minority women sustaining exercise at that level is high, yet is of sufficient intensity to be effective with respect to beneficial effects of CHD. The Specific Aims are to: 1: Compare the effects of low and moderate intensity of exercise in Mexican American and African American women on blood lipids, fat cell size and function, LDL particle size, body fatness and fat distribution, and exercise tolerance. 2: Determine the effects of low and moderate intensity of exercise on exercise maintenance in sedentary, obese minority women. 3; Explore the dose-response relationship of exercise volume, where volume is an interaction term of intensity X maintenance, to total serum cholesterol, triglycerides, HDL-C, LDL-C, body fatness, fat cell size, lipolysis, LDL particle size, and exercise endurance. Two experimental groups will be employed. Both randomized groups will walk 4 days a week, for 30 minutes a day. Group 1 will walk at 40 percent of target heart rate; Group 2 will walk at 65 percent of their target heart rate. This study is unique in that is proposes an interdisciplinary approach to the understanding of the biobehavioral mechanism underpinning exercise and its relationship to fat metabolism. This study, when completed, will answer certain questions: can exercise of a 48 week duration at levels below those known to decrease CHD risk produce significant changes in those risk factors? and, will the dose (frequency) of exercise produce a graded effect on the risk factors as measured by body composition, blood lipids, and fat cell size and function?